Method of stitching a corded seam

ABSTRACT

A method and apparatus for stitching a corded seam to join a pair of plastic or fabric material panels used primarily in manufacturing upholstered products. The seam comprises a single row of stitching which binds the several elements making up the seam. When stitching the seam in a conventional sewing machine with a cord piper attachment, an equal amount of back or tension pressure is applied to the two panels between which the seam is being placed as the panels are fed into the sewing machine.

United States Patent [191 Hamilton et al.

[ 1 Feb. 25, 1975 METHOD OF STITCHING A CORDED SEAM ['76] Inventors: Lillie Hamilton, 1034 W. 92 PL;

Lorretta McCrey, 8714 S. Sangamon, both of Chicago, Ill. 60620 [22] Filed: Nov. 26, 1973 [21] App]. No.: 419,112

[52] US. Cl. 112/139, 112/262 [51] Int. Cl D05b 35/06 [58] Field of Search 112/139, 150, 136,262

[56] References Cited UNITED STATES PATENTS 378,823 2/1888 Arnold 112/150 MacPherson 1 12/139 2,839,018 6/1958 Mulkey 112/139 Primary Examiner-H. Hampton Hunter Attorney, Agent, or Firm-Alter and Weiss [57] ABSTRACT A method and apparatus for stitching a corded seam to join a pair of plastic or fabric material panels used primarily in manufacturing upholstered products. The seam comprises a single row of stitching which binds the several elements making up the seam. When stitching the seam in a conventional sewing machine with a cord piper attachment, an equal amount of back or tension pressure is applied to the two panels between which the seam is being placed as the panels are fed into the sewing machine.

4 Claims, 6 Drawing Figures PATENTED P5329975 T3. 867. 890

FIG. I

PRIOR ART m .Jl' I 42 1 METHOD OF STITCHING A CORDED SEAM The present invention relates to an improved stitching method and apparatus, and in particular relates to the art of applying a straight, strong corded seam to a pair of plastic or fabric panels in a single step.

In the manufacture of upholstered furniture items, it is often necessary to form a sewn or stitched seam at the juncture of two material panels to form a cushion, seat cover, dinette chair covering, furniture covering or the like. The material from which the cover for the upholstered item is made may comprise a variety of fabric or plastic materials. For example, many of todays seat covers, cushions, upholstered chairs and the like are being fabricated from a plastic vinyl material, which is decorative and provides the furniture with a longer life. New processes of manufacture have made plastic vinyl materials available which have somewhat the texture and color design characteristics of cloth or fabric coverings, therefore increasing the popularity of upholstered furniture covered with this material. It is especially advantageous in homes having small children and pets, due to the durability of vinyl plastic under'continuous use.

Up to now, it has been common practice to use an end binding type of flat seam to join two vinyl plastic panels in fabricating an upholstered product. However, this proves unsatisfactory in many instances, such as where the upholstered item is subject to heavy, and repeated use. For example, the flat seams rip or pull apart, causing the product to separate.

It has been found that a corded seam could be used instead of a flat seam in fabricating plastic covers to add to the strength and appearance of the upholstered seam. However, further difficulties arose in attempting to apply a corded seam to heavy-duty vinyl plastic material panels. Initially, the method of fabricating the seam by known processes comprises three steps, which result in increased labor costs. In previous methods, a strip or piece of material first had to be wrapped around a cord element and stitched in place with the ends of the strip extending outward from the core element. In a second step, one material panel is stitched onto the ends of the strip surrounding the core element. The assembly is then turned over and a second material panel is stitched to the other side of the strip surrounding the core element. The result is a seam comprising multiple rows of stitches.

In addition to the time and labor required to form a corded seam using a three-step method, it was difficult to prepare straight seams using this method, and often the material panels would wrinkle as the corded seam was applied. Both of these results are obviously unsatisfactory from the standpoint of producing an attractive upholstered product. Among other problems, curved seams produced by this method would not fit a cushion as it was pinned.

When attempts were made to fabricate a corded seam between panels of vinyl plastic material, acceptable results could be obtained only if the material panels were made of clear, light weight vinyl plastic. Therefore, the use of heavy duty, durable vinyl material to fabricate upholstered products has been discontinued due to the failure of those skilled in the art to devise a satisfactory and economical method of making a satisfactory seam between panels of heavy duty vinyl.

Therefore, it is a primary object of our invention to produce an attractive, durable corded seam in a plastic or fabric upholstered furniture product.

It is a further object of our invention to provide a method and apparatus for producing a straight corded seam between two material panels whereby the panels do not wrinkle when applying the seam.

Still another object of our invention is to provide a method and apparatus for producing a straight, attractive corded seam between two material panels in a single stitching step.

It is an additional object of our invention to provide a method and apparatus for providing a corded seam between two material panels which resist separation under heavy load and repeated use.

Yet another object of the presently disclosed invention is to provide a method of applying a straight and attractive corded seam between heavy duty plastic vinyl upholstery panels.

According to one aspect of our invention, an apparatus is provided to surround a corded element with a piece of material and to locate the surrounded corded element at the stitching station of a conventional sewing machine. For this purpose, a standard cord piper is attached to the base of the sewing machine and the material and corded element are fed through the cord piper. First and second material panels are also located at the sewing station, one panel above the corded element, and one panel below. This sandwich-like assembly is next fed through the sewing machine where a single row stitch is applied to each panel and to the material surrounding the corded element. A uniform back or tension force is maintained on both material panels as they are fedthrough the stitching station of the sewing machine to produce a straight and sufficiently strong stitch.

The nature of a preferred embodiment of the invention should become more apparent from a study of the attached drawings in conjunction with the following specification wherein:

FIG. 1 is an illustration in cross-section of a flat seam commonly found in the prior art;

FIG. 2 is an exploded view in cross-section of the elements combining to provide a corded upholstery seam made in accordance with the teachings of the present invention;

FIG. 3 is a plan view of the sewing apparatus and cord piper forming part of the apparatus embodying the present inventive concepts;

FIG. 4 is a cross-sectional view of the material panels, strip of material and corded element as they are sewn at the stitching station of a standard sewing machine;

FIG. 5 is an elevation view of the sewing apparatus and cord piper of FIG. 3; and

FIG. 6 is a cross'sectional view of a finished corded upholstered seam made in accordance with the present inventive concepts.

Referring to FIG. I, there is shown a common flat seam such as found in the prior art to join two material panels l0, 12 which may comprise, by way of example, plastic cushions or seat covers. Each panel 10, 12 has a portion l4, 16 which extends inwardly adjacent a corresponding portion of another panel. To form the flat seam, a U-shaped piece of plastic material if; is disposed over the edges of portions 1.4 and 16. The edges of the U-shaped plastic 18 pass along portions l4, l6, and are looped back against themselves, as shown at 20. A stitch of nylon thread 54 or the like is applied through the two thicknesses of material portions 14, 16, and through four thicknesses of plastic material 18.

As stated previously, seams such as illustrated in FIG. i

panels are made of plastic or fabric upholstery covering or the like. Portions 26, 28 extend downward from panels 22, 24 and parallel to each other. A piece of material 30 such as vinyl plastic, fabric or the like extends over corded element 32. The ends of material 30 extend away from corded element 32 and are located between portions 26, 28 of material panels 22, 24. The seam is formed by holding portions 26 and 28 together with the ends of piece of material 30 therebetween, and applying a row of stitching 34 by using, for example, a standard sewing machine.

A standard attachment popularly known as a cord piper is used in conjunction with a sewing machine to produce the corded seam in accordance with our invention. A cord piper is shown in FIG. 3 and is generally designated by the numeral 36. A base plate 38 has mounted thereon a curved strip-material feeding device 40 which is adapted to receive a straight piece of material 42 approximately 1% inches wide and pass it through device 40 which contains an arbor therein (not shown). Feeding device 40 is located slightly above base plate 38 so that a piece of panel material 24, may be located between the feeding device and the base plate (FIG. As piece of material 42 is fed through device 40, it is wrapped into a substantially U-shaped configuration by the arbor in device 40 and the curvature of the inner wall of the material feeding device.

Adjacent one side of strip material feeding device 40 is a tubular member 44 adapted to receive a corded element 46 to be fed therethrough. Corded element 46 may consist of cotton, hemp, plastic or any other type of rope-forming material. Tubular member 44 is so positioned that as corded element 46 exits from the tubular member, piece of material 42 is wrapped around a portion of the circumference of corded element 46. This is best illustrated by referring to piece of material 30 and corded element 32 in FIG. 2.

At one end of strip material feeding device 40 is an exit port 48 through which corded element 46 and piece of material 42 emerge. Located adjacent exit port 48 is a reciprocating needle 50 which preferably forms a part of a standard sewing machine 52. Needle 50 is threaded with a nylon filament 54 as is well known in the art.

One side of base plate 38 has a portion 56 extending therefrom. Two slots 58 are provided in portion 56 through which screws 60 movably attach an arm 62 to base plate 38. Arm 62 is adapted to fit in a mating slot (not shown) on the pedestal of sewing machine 52 to hold cord piper 36 in place relative to needle 50.

In operation, first material panel 22 of the plastic or adapted to receive material panel 22. Material panel 22 is fed into sewing machine 52 in the direction shown by the arrow 66 (FIG. 3).

A second material panel 24 is also fed into sewing machine 52 beneath strip material feeding device 40 in the space between the feeding device 40 and base plate 38. Material panel 24 is fed in the direction shown by arrow 66.

Corded element 46 is fed into cord piper 36 through tubular member 44, and strip of material 42 is passed through feeding device 40. Material 42 is subsequently wrapped around cord element 46 as they both emerge from cord piper 36 adjacent the stitching station of the sewing machine.

As piece of material 42, corded element 46, and material panels 22, 24 approach the stitching station beneath needle 50, they form a structure such as illustrated in FIG. 4. With the ends of strip of material 42 sandwiched between panels 22 and 24, needle 50 applies filament or thread 54 through the four thicknesses of material to form the stitch binding the corded seam.

When feeding material panels 22, 24 into the stitching station beneath needle 50, it is an important aspect fabric comprising the upholstery cover to be seamed is 6 of the present inventive concept that a uniform back or tension pressure be applied to each material panel in the direction shown by arrow 65. In the illustrated embodiment, this pressure is applied manually by an operator gripping each panel 22, 24 and applying a slight tension pressure to each panel, as shown at 66, 68. It is important that substantially the same amount of tension pressure be applied to each material panel 22, 24 as they are fed through sewing machine 52. The pressure may be light, but must be balanced evenly between the material panels.

In the illustrative embodiment, the requisite tension pressure is applied manually to material panels 22, 24. However, it is also contemplated that automatic material feeding devices may be employed with our invention which use mechanical means to maintain a uniform back pressure on the material panels.

The finished seam is formed by pulling material panels 22, 24 over the corded element to form the structure shown in FIG. 6. If the tension pressure applied to material panels 22, 24 varies, the resulting seam will not be straight, and the material panels 22, 24 may wrinkle at the point where they are stitched to piece of material 42.

In keeping within the scope of our invention, material panels 22, 24 can be made of plastic material or fabric material. Also, the piece of material 30 surrounding core element 32 (FIG. 2) may be made of plastic, fabric or any other suitable material.

It will be understood that modifications and variations of the corded seam stitching method and apparatus disclosed herein may be resorted to without departing from the spirit of our invention and the scope of the appended claims.

We claim: I. In a method of stitching a corded upholstery seam in an automatic sewing device, the steps of:

surrounding a core element with a piece of material whereby the ends of said material extend adjacent one another and away from said core element;

locating one end of a first material panel along one of said ends of said piece of material adjacent said core element;

6 locating one end of a second material panel along the 2. The method of claim 1 wherein said piece of mateother of said ends of said piece of material adjacent rial and said material panels are fabric materials. said core element, and 3. The method of claim 1 wherein said piece of matestitching said piece of material and said material panrial and said material panels are plastic materials.

els together on a common seam in said automatic 5 4. The method of claim 1 wherein said material pansewing device while applying an equal amount of els are fabric materials. tension pressure to each of said material panels. 

1. In a method of stitching a corded upholstery seam in an automatic sewing device, the steps of: surrounding a core element with a piece of material whereby the ends of said material extend adjacent one another and away from said core element; locating one end of a first material panel along one of said ends of said piece of material adjacent said core element; locating one end of a second material panel along the other of said ends of said piece of material adjacent said core element, and stitching said piece of material and said material panels together on a common seam in said automatic sewing device while applying an equal amount of tension pressure to each of said material panels.
 2. The method of claim 1 wherein said piece of material and said material panels are fabric materials.
 3. The method of claim 1 wherein said piece of material and said material panels are plastic materials.
 4. The method of claim 1 wherein said material panels are fabric materials. 